Amazing work, very cool to see a Jumping Flash inspired game! Takes me back to the 90s memories of the first playstation demo disk. The game runs pretty well and looks great. The art style is nice but it could use a little more art direction to take it to the next level. But this is already more then serviceable. Also the video intro and win screen were awesome too!
I loved the first level, really good stuff. The second level I don't like so much. It completely throws away the formula and is way too punishing. I did also hack the game to skip to the boss fight which was a good start to a boss fight but I pretty much stood in one place shooting and jumping to beat it.
I think this game could be killer with a little more polish and replace level 2 with an improved version. Maybe play through Jumping flash or watch a playthrough on YouTube for ideas and inspiration. The current level 2 is so tough if you still want to keep it, maybe have it as an unlockable level after you win.